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rr arec 'EROLD L. BATTING AND HOWARD H. GROSS, JR.. 0F CHICAGO, ILLINOIS.

LIGHT-PROJECTOR.

Application led March 1G, 1916.

To all whom t may concern:

Be it known that we, HAROLD L. BATTING, a subject of the King of Great Britain, and HOWARD H. Gross, Jr., av citizen of the United States, both residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Light-Projectors, of which the following is a specification.

This invention relates to improvements in light projectors and morev particularly to projectors adapted for use as automobile head lights.

With the development and refinement of the motor car there .has been, of late years, a decided tendency to increase the capacity of the lights for better illumination of a road-Way in night driving. This development has usually taken the form of increasing the efliciency of the reflector and increasing the candle power of the electric light, the electric light now practically dominating the field because of its convenience and efficiency.

The powerful and brilliant rays thrown by such lamps, and their concomitant blinding and dazzling effect are too well known to need discussion. rlhe fact that these lamps of the commonly used type are so brilliant and blinding as to be a menace to the public is conclusively shown by the fact that many States and cities have passed laws limiting the use of such lights to country driving only, it being necessary to diminish the1r power when within settled districts.

Several lighting systems have been developed in an attempt to comply with such laws, such for example as using smaller auX- iliary lamps of lower candle power for city driving; decreasing the candle power of the lamp by switching Athem into series and consequently operating them on one-half of their normal voltage; using frosted or clouded glass in the door of the lamp; placing a hood over the upper half of the lamp; utilizing controllable shutters to partially deflect the light toward the road-way or for cutting it ofi' entirely; and by shaping the door glass in multi-prismatic form in an ebrt to direct the rays of light to the desired points. The diiiculty with most of the above structures is, however, that the efiiciency of the lamp as a light projector is decreased and a poor lighting of the roadw ay results.

Specification of Letters Patent.

Patented Jann5 2, 191'?.

serial No. 84,532.

The requirements of certain of the State laws are most exacting, one in fact requiring that the light be of such brilliancy as to enable one to see clearly certain specified objects a certain number of feet ahead of the car; that a certain number of feet ahead of the car the light be visible to a pedestrian, but without glare or dazzling effect; and that a sufficient light be thrown a certain number of feet each side of the car to make clilrbstones and similar objects readily vis- 1 e.

The principal object of our invention is to provide a highly eflicient light projector which will provide a maximum illumination of a roadway and still comply with the most rigid safety requirements, thus increasing the safety of city driving, as well as country driving without bothering the driver with the manipulation of dimmers or other appliances.

A further object of the invention is to provide a lamp which will project the brightest and most concentrated rays in a path beginning at about 40 feet ahead of the car, a. secondary set of rays of lesser brilliancy preceding the primary rays, as they are thrown 'upon the roadway, and having a greater angle of diffusion at the sides of the roadway and a third set of rays of very much less brilliancy emanating directly from the source of light without reflection and illuminating the roadway directly in front of the car and at both sides.

A further object of the invention is to so construct the light projecting parts of the apparatus as to 'make them readily insertible in the shell of the usual form of headlight by simply removing the parabolic reflector with its lamp socket and replacing it by our improved apparatus, using the same screw fasteners for holding it in place.

Still another object of the invention is to so arrange the reflecting surfaces as to utilize a portion of the parabolic reflector such as is commonly used in headlights now on the market as one of the reflectors of our apparatus, thus reducinvl the cost to theI consumer when making an installation in lamps already in use.

@ther and further objects will become apparent to those skilled in the art from a consideration of the following description and drawings wherein- Figure l is a front elevation of our improved light projector as embodied in an automobile head-light. Fig. 2 is a diagrammatic view illustrating the disposition of the rays of various intensities as thrown upon a roadway. Fig.,3 is a central vertical sectional view through the head light shown in Fig. 1, and Fig. L1 is a central horizontalsectional view.

In the drawings we have illustrated our improved light projector as embodied in an automobile head light having the same external appearance or shell formation as the common type of head lights which are now well established as a standard.

W'e have arranged the light projecting parts and the-.bulb mounting so that they may be handled as an entirety, all being secured to, and carried by a flat disk, the diameter of which is substantially that of the annular ring mounting in the common type of head light for supporting the reflector.

With this arrangement the reflector .may

be quickly removed from head lights already in use and our apparatus substituted by the use of a screw driver alone, the flat disk having been drilled in the process of manufacture with holes to register with the tapped holes in the reflector supporting ring. It will also be evident that because of this arrangement of mounting, the lamp vmay be produced by a lamp manufacturer with his stock patterns for casings, door parts, hinges, etc.

In general the projector comprises a parabolic reflector positioned with its axis perpendicular and a lamp at approximately its focal center. ola is cut away on a vertical plane and directly above the rear edge of the parabolic reflecting surface is a plane reflecting mirror, the upper edge of which is inclined forwardly to position its surface at an angle of approximately 45 degrees to the horizontal. The front upper segment of the lamp bulb is blackened to cut off' the passage of rays forwardly and upwardly. Y

From this general description of the apparatus it will be evident that rays of light projected-from the bulb upon the parabolic reflector will be directed against the inclined plane reflector on lines substantially parallel to the axis of the parabola and since the plane reflector is inclined at an angle slightly less than 45 to the horizontal, are then reflected forwardly on lines angling slightly downwardly from the horizontal. As a result, not any of these primary rays, as we will term them and which are indicated in the drawing by the character (m) are visible to the eye of an observer positioned above a horizontal plane passing through the top of the plane reflector and are concentrated upon the roadway, beginning at a point about l() feet in front of the car and extending from that point forward in a comparatively narrow strip, the

A front sector of the parab-.

sides of which diverge but slightly, to a distance depending upon the power of the light source. Vhereas in practice we have found it best to have the primary rays strike the roadway at a point about 40 feet ahead of the car, this distance may be varied to suit by changing the angle of the plane reflector. The path-way of light resulting from the primary rays is graphically illustrated in Fig. 2 as approximately lying within the boundaries of the line indicated by the char'- acter ,(a). yAnother set of rays projected from the' lamp, which we will term the secondary rays and designate by the letter (y), result from the reflecting from the plane mirror of rays passing to it directly from the source of light without being affected by the parabolic reflector. The illumination resulting from these rays will, of course, be

less brilliant than that `resulting from the primary rays, but will be diffused at a wider angle and will meet theroadway nearer to `the front of the car. The approximate field in the roadway upon which the secondary rays will be cast is represented as being within the line indicated by the letter (b) in Fig. 2.

' The rays projected directly forwardly and downwardly from the source of light itself, unaffected by either of the reflectmg surfaces, and which we will term the tertiary set of rays (e), these being the least brilliant of the three sets of rays, strike the roadway directly in front of the car and extend at a wide angle to each side, the approximate rear boundary of these rays as they are projected upon the roadway, being indicated in Fig. 2, by line (c). Whereas in the diagrammatic lay out of the three light boundaries of different intensity as project- Aed upon a roadway we have indicated the beginning of each set by a solid line we have found that in actual use the rays from each set blend into its neighboring set smoothly and without causing black streaks or spots in the resultant illumination of the roadway.

In th'e embodiment of our invention illustrated in the drawings, 1() represents an automobile head light shell or casing of generally parabolic formation having its forward edge portion beaded as at 11 to provide a shoulder or stopV against which the hinged front door indicated in general by the numeral 12 closes.

Secured within the front edge of the casing is an annular ring 13 provided withtapped .openings 14 at suitable intervals around its periphery. It is to this annular ring 13 that the usual type of parabolic reflector such as indicated in dotted lines at 15 in F10. 3 is secured at its periphery by means of the screws 16. In place of the parabolic reflector 15 we position within the lamp a flat disk 17 upon the rear or inner face of which is mounted the projecting apparatus, the disk in turn being secured Within the casing by means of the same screws 16, passing through holes drilled in the disk to register with the tapped openings 14 1n the annular ring 13.

At the rear of the disk 17 and near its bottom We have mounted a portion of a parabolic reflector which is formed by cut' ting a segment therefrom on a plane parallel to the axis of the parabolal and positioned at one side thereof a distance slightly greater than the radius of the lamp bulb. This parabolic reflector which is indicated by the numeral 18 isA positioned with its axis in a vertical line and with its cut away portion lying aga-inst the rear face of the disk 17. The lamp socket 19 carried at the bottom of the parabolicl reflector is So positioned as to insure the filament of the lamp bulb 20 lying at approximately the focal center of the parabolic surface.

In practice it is, of course, impossible to locate the source of light at a mathematical point, but We have found that a lamp filament in the form of an inverted V as shown in Fig. 1 is very effective. By positioning the apex of the V shaped filament at approximately the focal center of the parabolic reflector, it is evident that the major portion of the source of light is somewhat below the focal point and rays emanating therefrom on being reflected by the parabolic reflector will diverge slightly and the light projected upon the roadway will cover a larger area than Would otherwise be the case. As showing typical reflected rays we have in Fig. 3 positioned the point 21 which is taken as a light source slightly below the focal point of the parabola and the plane reflector inclined `at approximately 43 to the horizontal. The lamp socket is suitably connected by wire 22 to the plug connector .23 provided in the casing 10.

Mounted above the parabolic reflector 18 at the rear thereof is a plane reflector which in the present instance comprises a glass mirror 24 with its lower edge 26 positioned near the rear edge of the parabolicreflector 18 and extending forwardly and upwardly at an angle slightly less than 45 degrees to the horizontal, and terminating at its upper edge approximately on a vertical line passing through the focal axis of the parabola. From the straight upper edge 25 of the mirror 24 the sides curve downwardly to its lower edge 26. The curvature of the side edges of the plane mirror conform approximately to the .outline of the parabolic reflector as projected upon the inclined plane determined by the mirror 24. This mirror is mounted in a sheet metal backing 27 se cured at its edges, as at 28, to a perpendicular metal wall 29 which curves around the rear edge of the parabolic reflector and is secured to the edge thereof. The forward vertical edges 30 of the wall 29 extend from the ends of the mirror edge 25 down to the forward upper edge of the parti-parabolic reflector 18. The front of the disk 17 is cut away to correspond with the front opening of the projecting apparatus, the opening having a straight upper edge cooperating with the upper edge 25 of the mirror, arallel side edges corresponding with the s1des 30 of the backing wall 29 and its downward wall curved, as at 31, to conform to the cut away edge of the parabolic reflector.

The front upper sector of the lamp bulb 20 is blackened as at 32 providing an opaque screen to intercept those rays of light emanating directly from the source lof light that otherwise would be projected upwardly ahead of the plane reflector. The only rays which emanate directly from the source ofv light and pass outwardly through the casing opening are those which have been previously referred to as the tertiary rays (a).

The secondary rays (y) are reflected rays resulting from rays (y1) being thrown directly from the source of light 21 upon the mirror 24, and reflected on paths indicated at in Fig. 3. The primary rays pass from the source of light 21 on lines indicated as at (m1) to the vparabolic mirror from which they are projected upwardly on lines (m2) substantially arallel with the axis of the parabolic re ector against the plane mirror and from thence reflected ahead on the lines (m) previously described.

The casing is provided with suitable lugs 35 which project outwardly from the sides for mounting upon the lamp brackets of a car and at its front is provided with a door member 12 in which is mounted the usual form of curved glass front 36. The door is hinged at one side, as at 37, and provided with a thumb nut fastening lock 38, at its opposite side.

ln practice it is of course impossible to manufacture a mathematically perfect parabolic reflector on a commercial scale, and with variations of curvature it will be found necessary to vary the focus of the lamp filament, or thefangle of the plane reflector, or both. In the claims reference to a parabolic reflector will be understood to mean a relector of generally parabolic curvature.

Whereas we have illustrated and described our improved light projecting apparatus as applied to an automobile head light, it is obvious that it may be applied to other forms of lamps such for example as are used on street cars, locomotives, boats and the like, and that various changes may be made therein without departing from the spirit and scope of the appended claims.

Having described our invention, whatwe claim is 1. 1n a light projector, the combination with a parabolic reflector positioned with its axis approximately perpendicular to the horizontal the front edge of said reflector terminating in a vertical plane at substantially right angles to the path of the projected light and adjacent the axis of the reflector, of a source of light located at approximately the focal point of said reflector, and a substantially flat reflector inclined to the horizontal and positioned to intersect rays of light reflected by the parabolic reflector.

2. In a light projector, the combination with a parabolic reflector positioned with its axis approximately perpendicular to the horizontal the front edge of said reflector terminating in a vertical plane at substantially right angles to the path of the projected light and' adjacent the axis of the reflector, of a source of light located at approximately the focal point of said reflector, and a substantially flat reflector positioned above the vparabolic reflector and inclined at approximately 45 degrees to the horizontal.

3. In a light projector the combination with a parabolic reflector positioned with itQ axis approximately perpendicular to the horizontal, of a source of light located at approximately the focal point of said reflector, and a substantially flat reflector inclined at 45 degrees or less to the'horizontal and positioned to intersect rays of light reflected by the parabolic reflector, the space between said source of light and plane reflector being unobstructed.

4. In alight projector the combination with a parabolic reflector positioned with its axis approximately perpendicular to the horizontal, of a source of light located at approximately the focal point of said reflector, a portion of the forwardly extending part of 'said parabolic reflector being cut away at points below the focal center thereof, and aplane reflector inclined to the horizontal and positioned to intersect rays of light reflected by the parabolic reflector.k

.5. In a light projector the combination with a parabolic reflector positioned with its axis approximately perpendicular to the horizontal, of a source of light located at l approximately the focal point of saidl reflector, the front portion of said reflector being cut away to points below the focal point, and a plane reflector inclined at approximately 45 degrees to the horizontal and positioned to intesect rays of light reflected by the parabolic reflector'.

6. In a light projector the combinationwith a parabolic reflector positioned with its axis vertical, of a source of light positioned at approximately the focal point of said reflector,

- a plane reflector above the parabolic reflector and positioned at an angle of 45 degrees or less to the horizontal, the front portion of said parabolic reflector being cut away to points below the focal point thereof, and an opaque screen positioned to intercept those rays of light emanating from the source of light and passing upwardly and forwardly that otherwise would not bev intercepted by the plane reflector, said screen extending downwardly to approximately the horizontal level of .the focal point of the parabolic reflector.

7 In a lamp the combination of a casing open at its forward edge, a disk detachably secured at its periphery to the open edge portion of said casing, a parabolic reflector positioned with its axis vertical, a plane reflector positioned above` said parabolic reflector, a source of light positioned at approximately the focal point of saidA para` bolic reflector, and means for mounting the source of light, and both reflectors upon the rear face of the aforesaid disk.

8. In a light projector the combination with a parabolic reflector positioned with its axis approximately vertical, al plane re flector positioned above the parabolic reflector but inclined tothe horizontal with its upper forward edge terminating approximately in a vertical plane passed through the focal point of the parabolic reflector, the side and bottom edges of the plane reflector conforming to the outline of the parabolic reflector as projected upon the plane in which the plane reflector lies, and a source of light positioned at approximately the focal lpoint of the parabolic reflector.

9. In a light projector the combination of a casing having an open front end, a disk removably mounted in the front of said casing, a parabolic reflector, positioned with its axis approximately vertical, and having its front portion cut away to points below the focal point of the reflector, a plane reflector positioned above the parabolic reflector and inclined to the horizontal, and means for mounting the, parabolic and plane reflectors at the rear of cthe disk, said disk having an opening therein, the lower edge of which conforms approximately to the curvature of the cut away portion of the parabolic reflector, and thepupper edge of which lies in approximately the same horizontal plane as the upper edge of` the plane reflector.

10. In a light projecting apparatus tneparabolic reflector, a plane reiector with its upper edge inclined forwardly, the said vertical wall terminating at its intersection with the plane reiector, means for mount-l ing said plane reiector upon the Vertical wall, and means for securing the vertical Wall and parabolic reiector to the rear faceV of the said disk, the disk having an opening I therein conforming in outline at its sides.

to the intersection therewith of the vertical wall, its upper edge conforming to the uphands.

HAROLD L. BATTING. HOWARD H. GROSS, JR.

`In the presence of- STANLEY W. Coon, MARY F. AILEN. 

